/*
 * Copyright 2002-2017 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.aop.support;

import java.io.Serializable;
import java.lang.reflect.Method;

import org.springframework.aop.ClassFilter;
import org.springframework.aop.IntroductionAwareMethodMatcher;
import org.springframework.aop.MethodMatcher;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;

/**
 * Static utility methods for composing {@link MethodMatcher MethodMatchers}.
 *
 * <p>A MethodMatcher may be evaluated statically (based on method and target
 * class) or need further evaluation dynamically (based on arguments at the
 * time of method invocation).
 *
 * @author Rod Johnson
 * @author Rob Harrop
 * @author Juergen Hoeller
 * @see ClassFilters
 * @see Pointcuts
 * @since 11.11.2003
 */
public abstract class MethodMatchers {

    /**
     * Match all methods that <i>either</i> (or both) of the given MethodMatchers matches.
     *
     * @param mm1 the first MethodMatcher
     * @param mm2 the second MethodMatcher
     * @return a distinct MethodMatcher that matches all methods that either
     * of the given MethodMatchers matches
     */
    public static MethodMatcher union(MethodMatcher mm1, MethodMatcher mm2) {
        return new UnionMethodMatcher(mm1, mm2);
    }

    /**
     * Match all methods that <i>either</i> (or both) of the given MethodMatchers matches.
     *
     * @param mm1 the first MethodMatcher
     * @param cf1 the corresponding ClassFilter for the first MethodMatcher
     * @param mm2 the second MethodMatcher
     * @param cf2 the corresponding ClassFilter for the second MethodMatcher
     * @return a distinct MethodMatcher that matches all methods that either
     * of the given MethodMatchers matches
     */
    static MethodMatcher union(MethodMatcher mm1, ClassFilter cf1, MethodMatcher mm2, ClassFilter cf2) {
        return new ClassFilterAwareUnionMethodMatcher(mm1, cf1, mm2, cf2);
    }

    /**
     * Match all methods that <i>both</i> of the given MethodMatchers match.
     *
     * @param mm1 the first MethodMatcher
     * @param mm2 the second MethodMatcher
     * @return a distinct MethodMatcher that matches all methods that both
     * of the given MethodMatchers match
     */
    public static MethodMatcher intersection(MethodMatcher mm1, MethodMatcher mm2) {
        return new IntersectionMethodMatcher(mm1, mm2);
    }

    /**
     * Apply the given MethodMatcher to the given Method, supporting an
     * {@link org.springframework.aop.IntroductionAwareMethodMatcher}
     * (if applicable).
     *
     * @param mm               the MethodMatcher to apply (may be an IntroductionAwareMethodMatcher)
     * @param method           the candidate method
     * @param targetClass      the target class (may be {@code null}, in which case
     *                         the candidate class must be taken to be the method's declaring class)
     * @param hasIntroductions {@code true} if the object on whose behalf we are
     *                         asking is the subject on one or more introductions; {@code false} otherwise
     * @return whether or not this method matches statically
     */
    public static boolean matches(MethodMatcher mm, Method method, @Nullable Class<?> targetClass, boolean hasIntroductions) {
        Assert.notNull(mm, "MethodMatcher must not be null");
        return ((mm instanceof IntroductionAwareMethodMatcher &&
                ((IntroductionAwareMethodMatcher) mm).matches(method, targetClass, hasIntroductions)) ||
                mm.matches(method, targetClass));
    }


    /**
     * MethodMatcher implementation for a union of two given MethodMatchers.
     */
    @SuppressWarnings("serial")
    private static class UnionMethodMatcher implements IntroductionAwareMethodMatcher, Serializable {

        private final MethodMatcher mm1;

        private final MethodMatcher mm2;

        public UnionMethodMatcher(MethodMatcher mm1, MethodMatcher mm2) {
            Assert.notNull(mm1, "First MethodMatcher must not be null");
            Assert.notNull(mm2, "Second MethodMatcher must not be null");
            this.mm1 = mm1;
            this.mm2 = mm2;
        }

        @Override
        public boolean matches(Method method, @Nullable Class<?> targetClass, boolean hasIntroductions) {
            return (matchesClass1(targetClass) && MethodMatchers.matches(this.mm1, method, targetClass, hasIntroductions)) ||
                    (matchesClass2(targetClass) && MethodMatchers.matches(this.mm2, method, targetClass, hasIntroductions));
        }

        @Override
        public boolean matches(Method method, @Nullable Class<?> targetClass) {
            return (matchesClass1(targetClass) && this.mm1.matches(method, targetClass)) ||
                    (matchesClass2(targetClass) && this.mm2.matches(method, targetClass));
        }

        protected boolean matchesClass1(@Nullable Class<?> targetClass) {
            return true;
        }

        protected boolean matchesClass2(@Nullable Class<?> targetClass) {
            return true;
        }

        @Override
        public boolean isRuntime() {
            return this.mm1.isRuntime() || this.mm2.isRuntime();
        }

        @Override
        public boolean matches(Method method, @Nullable Class<?> targetClass, Object... args) {
            return this.mm1.matches(method, targetClass, args) || this.mm2.matches(method, targetClass, args);
        }

        @Override
        public boolean equals(Object obj) {
            if (this == obj) {
                return true;
            }
            if (!(obj instanceof UnionMethodMatcher)) {
                return false;
            }
            UnionMethodMatcher that = (UnionMethodMatcher) obj;
            return (this.mm1.equals(that.mm1) && this.mm2.equals(that.mm2));
        }

        @Override
        public int hashCode() {
            int hashCode = 17;
            hashCode = 37 * hashCode + this.mm1.hashCode();
            hashCode = 37 * hashCode + this.mm2.hashCode();
            return hashCode;
        }
    }


    /**
     * MethodMatcher implementation for a union of two given MethodMatchers,
     * supporting an associated ClassFilter per MethodMatcher.
     */
    @SuppressWarnings("serial")
    private static class ClassFilterAwareUnionMethodMatcher extends UnionMethodMatcher {

        private final ClassFilter cf1;

        private final ClassFilter cf2;

        public ClassFilterAwareUnionMethodMatcher(MethodMatcher mm1, ClassFilter cf1, MethodMatcher mm2, ClassFilter cf2) {
            super(mm1, mm2);
            this.cf1 = cf1;
            this.cf2 = cf2;
        }

        @Override
        protected boolean matchesClass1(@Nullable Class<?> targetClass) {
            return (targetClass != null && this.cf1.matches(targetClass));
        }

        @Override
        protected boolean matchesClass2(@Nullable Class<?> targetClass) {
            return (targetClass != null && this.cf2.matches(targetClass));
        }

        @Override
        public boolean equals(Object other) {
            if (this == other) {
                return true;
            }
            if (!super.equals(other)) {
                return false;
            }
            ClassFilter otherCf1 = ClassFilter.TRUE;
            ClassFilter otherCf2 = ClassFilter.TRUE;
            if (other instanceof ClassFilterAwareUnionMethodMatcher) {
                ClassFilterAwareUnionMethodMatcher cfa = (ClassFilterAwareUnionMethodMatcher) other;
                otherCf1 = cfa.cf1;
                otherCf2 = cfa.cf2;
            }
            return (this.cf1.equals(otherCf1) && this.cf2.equals(otherCf2));
        }
    }


    /**
     * MethodMatcher implementation for an intersection of two given MethodMatchers.
     */
    @SuppressWarnings("serial")
    private static class IntersectionMethodMatcher implements IntroductionAwareMethodMatcher, Serializable {

        private final MethodMatcher mm1;

        private final MethodMatcher mm2;

        public IntersectionMethodMatcher(MethodMatcher mm1, MethodMatcher mm2) {
            Assert.notNull(mm1, "First MethodMatcher must not be null");
            Assert.notNull(mm2, "Second MethodMatcher must not be null");
            this.mm1 = mm1;
            this.mm2 = mm2;
        }

        @Override
        public boolean matches(Method method, @Nullable Class<?> targetClass, boolean hasIntroductions) {
            return MethodMatchers.matches(this.mm1, method, targetClass, hasIntroductions) &&
                    MethodMatchers.matches(this.mm2, method, targetClass, hasIntroductions);
        }

        @Override
        public boolean matches(Method method, @Nullable Class<?> targetClass) {
            return this.mm1.matches(method, targetClass) && this.mm2.matches(method, targetClass);
        }

        @Override
        public boolean isRuntime() {
            return this.mm1.isRuntime() || this.mm2.isRuntime();
        }

        @Override
        public boolean matches(Method method, @Nullable Class<?> targetClass, Object... args) {
            // Because a dynamic intersection may be composed of a static and dynamic part,
            // we must avoid calling the 3-arg matches method on a dynamic matcher, as
            // it will probably be an unsupported operation.
            boolean aMatches = this.mm1.isRuntime() ?
                    this.mm1.matches(method, targetClass, args) : this.mm1.matches(method, targetClass);
            boolean bMatches = this.mm2.isRuntime() ?
                    this.mm2.matches(method, targetClass, args) : this.mm2.matches(method, targetClass);
            return aMatches && bMatches;
        }

        @Override
        public boolean equals(Object other) {
            if (this == other) {
                return true;
            }
            if (!(other instanceof IntersectionMethodMatcher)) {
                return false;
            }
            IntersectionMethodMatcher that = (IntersectionMethodMatcher) other;
            return (this.mm1.equals(that.mm1) && this.mm2.equals(that.mm2));
        }

        @Override
        public int hashCode() {
            int hashCode = 17;
            hashCode = 37 * hashCode + this.mm1.hashCode();
            hashCode = 37 * hashCode + this.mm2.hashCode();
            return hashCode;
        }
    }

}
